The prior art filter apparatus constructed of plastics and having inlet and outlet connections either in the sides of the filter apparatus or in the ends of these structures, tend to deform or burst apart and cause leakage when subjected to high pressures of the order of say 100 psi. Such a filter structure tends to lose any safety factor which had been provided and would become hazardous. Thus, for example, the prior art filters of plastic construction can only stand about 100-150 psi maximum, when larger diameter filter vessels are employed. This type of filter vessel is generally made of plastics, since steel or other alloys corrode in water, acids, bases and other chemicals.
While a filter vessel can be made of plastic with round or dome heads that will take high pressure, there is the problem of putting inlet and outlet connections on this vessel of a size large enough to handle the fluid volumes and keep them from bursting and leaking at high pressure.
Illustrative of the prior art are the filter apparatus of U.S. Pat. Nos. 3,696,933 and 3,186,148.
It is an object of the present invention to provide a filter apparatus which will withstand high pressures, and at the same time have a high safety factor. Another object is the provision of a high pressure fluid or gas filter having a unique filter block structure.